Machine for turning lasts and the like irregular forms



March 5, 1935.

Filed Sept. 12. 1951 MACHINE FOR TURNING LASTS AND THE LIKE IRREGULARFORMS 4 Sheets-Sheet 1 134 52 39 :13 43 E L o 34 35 o 16 o o L I E 41 2527 f 25 ,L 33 105 21 e L. 2 42 0 o o o O o 14 17 m 12 12s 66 2 e2 100 so1- o o I i 4 I: I" 9 141 127 -14z 150 A A 2 72 1 ,fzzvczzi' i a ay"March 5, 1935 MACHINE FOR TURNING LASTS AND THE LIKE IRREGULAR FORMS 'H.W. SPRAGUE Filed Sept. 12. 1931 4 Sheets-Sheet 2 March 5, 1935. H. w.SPRAGUE 1,993,632

N? LASTS AND THE LIKE IRREGUIJAR FORMS MACHINE FOR TURNI 4 Sheets-Sheet5 Filed Sept. 12. 1951 March 5, 1935. H. w. sPRAeuE TURNIkiG LASTS ANDTHE LIKE IRREGULAR FORMS Patented Mar. 5, 1935 UNITED STATES PATENT' OE:

MACHINE FOR TURNING LASTS AND THE LIKE IRREGULAR FORMS Harold W.'Sprague, Brockton, Mass. -Application September 12, 19 31, Serial No.562,529

' 2 Claims. (01. 142-15) My present invention is a novel and improvedmachine adapted primarily. for automatically cutting and formingirregularly shaped articles such as a shoe last, wherein the contour ofa finished model is utilized and which. model the cuttinginstrumentalities reproduce from a larger block.

An important object of my present invention is the provision of meanswhich will enable the cutting devices to follow much smaller and moreintricate curves, particularly concave curves on the model and toreproduce such contours in the work being cut. I

Heretofore in turning apparatus of similar kind it has been universallycustomary to utilize'a Wheel to follow the contour of the model. Thiswheel actuates a swinging frame carrying the model and block to be out,and originally in last turning lathes such model wheels were from twelveinches to thirteen inches in diameter. Such a model wheel, however,could not follow an internal or concave curvature of smallerdiameterthan that of the Wheel itself, but would bridge across any contour ofthe model ona concave curvature of lesserdiameter than that of thewheel. With theco-nstantly changing designs on shoe lasts and moreinvolved contours, such model wheels were reduced in diameter untilseven or eight-inches whichseemed to be the smallest. diametercommercially and practically possible and feasible, particularly wherethe axis of, rotation of the cutter head utilized was parallel with theaxis of rotation of the work. In order to overcome the difiiculty abovenoted in the effort to follow more sharply shaped lasts, the nextdevelopment was. toincline the axis of rotation of the cutter. head andto vary the shape, form and contour of the cutter itself. By this means,viz., inclining the cutter head axis to as sharp an angle as forty-fivedegrees, itwas possible to operate such lathes commercially and greatlyreduce the diameter of the model wheel. In my present invention I havedevised a novel cutter head shown, described and claimed more in detailin my copending application Ser. No. 555,445 now Patent No. 1,935,337,issued Nov. 14, 1933 and have devised a. novel form of follower tocontact with the model, whereby I am enabled to make a last with thecutter head mounted at right angles-the most eflicient and desirableposition with regard to the workand capable of following internalcontours and curvatures on a model with as small a radius asthreequarters of an inch or even less if desired.

An important advantage in the feature just described is that I may, bymy novel machine and apparatus, enable the cutter to more closely,accurately and completely followthe model than has heretofore beenpossible; enable-thecutter to even form such slightint'ernal recesses asnow required in lasts for use inmaking the metatarsal arch support ofthe shoe to be built on such lasts; thus substantially, and in manyinstances almost entirely eliminating the hand work heretofore requiredin finishing lasts.

A further important and novel feature of my present invention consistsin the arrangement and construction of my novel last lathe which permitsan electric motor to be utilized'to turn the cutter and yet which willentirely free the cutter from vibration of the motor and conversely freethe motor from any chattering which might beoccasioned by the cutterhead encountering diliicult portions of the work being operated on. Thusthe 'motor will run more smoothly and the cutter head will also run moresmoothly than heretoforepossible, increasing the efiiciency andsmoothness of the cutting action, eliminating noise and wear, and alsopermitting substantially increased speed of rotation of the cutter. r

This feature is most important in my present invention and theadvantages incident thereto will be readily appreciated by those skilledin this art. 1 In carrying out this feature of my invention I arrangethe motor and the cutter on separate carriages together with meansacting automaticallyto move both the motor carriage and the cuttercarriage simultaneously during the progress of the cutting action, asthe same are fed lengthwise of the work while each is free of thetransmission 'of the vibration of either to the other as above noted.Heretofore it has been customary to mount the motorand the cutter on thesame carriage and consequently both the weight of the motor and themotor vibration were transmitted to the cutter, resulting inunsatisfactory work, chattering andconseguently uneven operation of the,cutter and necessarily limiting the speed of rotation of both motor andcutter.

A .still further and important feature of my present machine andinvention is the novel ar rangement, construction and universaladjustability of thefollower on the model. 'As above noted, it has beenheretofore universally customary toutilize a wheel which would roll onthe model as it is turned and which would progress with the feedingaction of the cutter on the block being shaped.

Further features, novel combinations and advantages will be hereinaftermore fully pointed out and claimed.

Referring to the drawings, illustrating a preferred embodiment of mypresent invention,

Fig. 1 is a general view of my improved turning lathe;

Fig. 2 is a plan view of a portion of the frame carrying the cutterhead;

Fig. 3 is a fragmentary vertical cross sectional view illustrating thecutter head and motor on separate carriages; 1

Fig. 4 is a fragmentary View substantially at right angles of theshowing of Fig. 3;

Fig. 5 is a fragmentary view of the model ball and carrying devices;

Fig. 6 is a View of a modified form of adjustments for the model ball;

Fig. '7 is an enlarged cross sectional view of the model ball; I

Fig. 8 is an enlarged cross sectional view of the cutter head, shaftandbearings;

Figs. 9 and 10 are enlarged fragmentary views illustrating my novelcutter head as more fully described and claimed in said copendingapplication Ser. No. 555,445; and

Figs. 11, 12, 13, 14, and 16 are diagrammatic views illustrating theimpossibilities of a model wheel reproducing an. internal curve of lessdiameter than that of the wheel while graphically showing the facilityof my inventionv in reproducing such internal curved contours ofextremely small diameter.

Referring to the drawings, I utilize a well known and standard type oflast lathe construction comprising a set of vertical standards 1, 1,cross frames 2 and 3 provided with braces 4 from the upper end of thestandards to the cross frame 3. Mounted at the upper end of thestandards 1, 1, on pivots or studs 6, 6, is swung a swinging frame 12,12, carrying cross rods 13 and 14. The fixed frame work is arranged tocarry the cutter and the model contacting member. In my presentinvention this member is a spherical ball and the cutter 25 ispreferably as shown in my said copending application, Ser. No. 555,445,as already noted.

The swinging frame 12, 12 is arranged to carry the model 31, with whichthe member 30 is in contact and the block 26 on which the cutter 25 isoperated. In order to rotate the model 31 and the block 26 they aremounted on centers in the swinging frame and are arranged for rotationat the same speed. As shown in Fig. 1, cross bars 13 and 14 on theswinging frame are supported by braces 15, 15, which are pivotally se-.

cured to bracket members 16 and 17 respectively, these bracketsextending from 13 to 14 and being fixed in their respective positions.

Mounted between the brackets 16 and 17 on suitable journal bearings is ashaft 20 carrying a live center 21 to engage one end of the block 26,the opposite end being engaged on an idle center 27 carried by a bracket28 adjustably secured on the cross bars 13 and 14. This bracket has theusual adjustments sliding on the cross bars 13 and 14 to enable the sameto hold and secure in position a block 26 of any desired length.

The model 31 also mounted in the swinging frame is held by a live center33 passing through a suitable bearing on a bracket 34 fixed to the crossbars 13 and 14 and with a sliding bracket 35 adjustably securedto thecrossbars 13and 14 having a center 36 holding the opposite end of themodel last 31.

In order to rotate the block 26 and model 31 at the same speed, gearwheels, of similar diameter, 37 and 38 are mounted respectively onshafts of the live centers 21 and 33 and are turned by pinions 39 and 40on a shaft 41 mounted in suitable bearings on the fixed brackets 1'7 and34, as clearly shown in Fig. 1, said shaft 41 carrying a pulley 42 whichis rotated by a belt 43 from a pulley 44 secured in a bearing 45 mountedat the top of the machine and parallel to and near the axis of theswinging frame 12.

The pulley 44 has secured at the other end a corresponding pulley 46rotated by a belt 47 on a pulley 48 secured to a shaft 50 supported inrigid bearings at the upper part of the frame 1, 1 and carrying on itsouter end portion a pulley 51 rotated by a belt 52 connected to adriving pulley 53 on a shaft 54 driven by any suitable source of power.

The construction thus far described may be of any usual or standardtype'of lathe and the cutter head, model contact sphere and my noveldriving mechanism therefor will now be described.

Mounted on the cross frames 2 are the beveled guide and flat guide '61,the guide 60 being preferably beveled to fit within the groove of theguide 62 mounted thereon.

Slidably resting on the guide 62 and guide 61 is a frame work carryingthe cutter head comprising a base 66 substantially rectangular in formand of sufficient width to give a firm bearing on the guide 62 and guide61; said base having standards 67 and 68 carrying bearings at the upperportion for the cutter shaft '70 on which my novel form of cutter head25 is secured. As previously explained, I am enabled by my presentinvention to utilize a cutter head and shaft positioned substantially atright angles to the work or block 26. on which the cutter head 25operates and at right angles also to the line of feed of the cutterframe 66 as it is moved progressive- 1y on the guide 62 and guide 61,lengthwise of the block 26 during the cutting operation.

Furthermore, an important feature of my present arrangement, wherein thecutter head and shaft are thus positioned directly at right angles, isthat I am enabled to form the bearings for the cutter head and shaftcloser to the work and thus fit or secure the cutter head 25 veryclosely to the bearings of the cutter shaft 70. This eliminatesvibration, distortion, or springing of the cutter shaft,-a seriousdifficulty in prior constructions where the cutter head and shaft werepositioned at an acute angle and hence with the shaft extending arelatively long distance in front of the bearings in order to provide aclearance of the first bearing or that nearest the block and work. Along cutter shaft with the cutter at the end substantially removed fromthefirst bearing, as in old construction, causedconstant chattering,vibration, and other difficulties often necessitating a slow speed.

By my improved and novel arrangement, however, with the cutter headitself and all strains involved in the cutting action on hardwood, suchas rock maple, these prior difficulties are eliminated and I am enabledto rotate the cutter head at greatly increased speed if desired, thusinsuring smoother action, more uniform operation, and freedom fromvibration.

The cutter head 251is, as 'ex 'lain'ed in my said bearings on-thevertical supports 67 and 68 on the shaft 70 to. receive a belt '72connected with a pulley 73 rotated by an electric motor 75.

An important feature of my present improved machine is that the motor-75 is mountedseparately from the cutter shaft 70 thus eliminating fromthe cutter shaft any vibration of the motor and similarly eliminatingfrom the motor anyvibration caused from the cutter head. This is a mostimportant advantage in devices of the kind herein described, as Iprovide rigid supports for the cutter shaft directly on the fixed frameof the machine and separate and distinct rigid supports for the motor,also secured to the fixed frame work and then I provide means which willfeed both the motor and the cutter head during its progressive action,at the speed desired, lengthwise of the block 26 being out. Whileseparate feeding devices may be utilized both for the motor support andfor the cutter head, providing they are moved at substantially uniformspeed, yet I have devised a novel vibration-free connection between thecutter head and motor operable from one source of power.

The cutter head supporting frame has already been described and themotor support will now be described.

As shown in Figs. 2, 3, l and 5, I secure a pair of guide rods 76 and 77lengthwise of the line of feed desired for the cutter and motor. The rod'77 is preferably mounted in suitable sockets v'78 in the frame 1, 1(see Fig. 2), and the rod '76 may be similarly mounted, but as. hereinshown, I have secured one end to a socket 79 in the frame 1, 1, and theother end is mounted on a bracket 80 bolted at 81 to the member 2 and atits opposite end having a recess through which the shaft 77 is passedand carrying the socket 82 for the end of the rod 76. This gives amplelength for the travel of the support carrying the motor 75.

Mounted on the rods 76 and 77 by blocks 83 and 84 (see Figs. 3 and 4),is a cross brace 85 carrying a depending bracket 86 to which the motorsupport 87 is secured. Preferably I arrange this support 87 toconstitute a belt-tightener between the motor 75 and the pulley on thecutter head shaft 70. For this purpose the lower end of the bracket 86is recessed to receive a pivot pin 90 passing through correspondingrecesses in a pair of projecting ears or lugs 91 on the motor support87. Adjusting means to oscillate and lock in position the motor support87 on the pivot 90 is provided by a pair of adjusting screws 92 and 93(see Fig. 4). The adjusting screw 92 is arranged through a tapped recessthrough the bracket '86 in convenient position to bear against a portionof the motor support 87 and constitute a thrust bearing." The adjustingscrew 93 is threaded through a correspondingly tapped lug 94 also on thebracket 86 and passesfreely through an opening in the adjacent portionof the motor support 87 to constitute a tightening screw.

By manipulating the thrusting screw 92 and tightening screw 93 the motorand support will be oscillated on the pivot 90 and thus operate as abelt-tightener, as above explained.

With the motor carrying support thus mounted work.

independently onthe rods 76 and '77, andslidable freely thereon and withthe cutter shaft frame mounted on the slides 62 and 61, it will thus beseen that each is independently supported on the frame work andtransmission of vibrations from one to the other is eliminated. This isan important feature, as above explained, and results in a greatlyincreased smoothness of operation of the lathe, permitting added speed.

In order to move the cutter carrying slide and motor carrying slide inunison I impart feeding motion to'the cutter slide 66, as willbeexplained, and move the motor slide therewith by securing to the underpart of the cutter slide 66 a depending member 96 fixed to the cutterslide 66 in N convenient position to engage the blocks 83 and 84supporting the motor. Preferably I arrange the blocks 83 and 84 slightlyspaced on the rod '77. Thus with the depending member 96 therebetweenmovement lengthwise of the rods 76 and 77 will be imparted to the motorsimultaously with the corresponding movement of the cutter carriage 66.

I may find it desirable to mount the cutter shaft '70 in ball bearings,although this is optional; but in view of the smooth operation of myseparately slidable motor and cutter supports, it is feasible in thisconstruction, and as shown in Fig. 8, ball bearing mounting and racewaysof any desired form are illustrated at 193. I also provide the usualhand wheel 194 on the cutter shaft 70, which may be integral with thepulley 71 The slide carrying the model contact member which at thepresent instance is -my novel spherical ball 30 is of usual form,comprising the carriage 100 mounted to slide on the guides 62 and 61, asexplained in connection with the cutter carrying frame,- and as clearlyshown in Fig. 5. The carriage 100 has supports 101 and 102 for the plate103. Said plate has a pair of dovetailed grooves in which the modelcarrying slide ,105 is adapted to move and may be locked in positionwhere desired by rotation of the locking nut 106 tapped through athreaded recess in a convenient portion, as shown'in Figs. 4 and 5. Theslide is moved inwardly or outwardly for adjustment of the contactmember 30 on the the slide 105, as shown in Figs. 5 and 7, or I maysecure same in apivotal position, as shown in Fig. 6.

Referring toFigs. 5 and '7, the slide 105 is preferably recessed asindicated at 116, to receive the support 107 on which the contact ball30 is mounted. A pair of screws 108 tapped into the support 107 throughcorresponding countersunk recesses in the slide 105, as clearly shown inFig. 7, secures the same to the slide. In order to mount the contactsphere or ball 30, which is to roll upon the model and effect a swingingof the frame, I provide at the end of the support 107 a stud 110preferably shouldered, as shown at 111. to constitute a support andpivot for the ball30. I also bevel the outer portion of the support 107as shown at 112, which aids in giving clearance to this member and topermit the ball 30 to follow inturned or ccncaved curves of extremelysmall radius.

In order to mount the ball 30 so that it will be firmly held and yetturned freely on the shoulder stud 110, I bore through the stud 110, asshown.

I may secure the member 30 rigidly to the head of the retaining screw115.

Referring to the modified form shown in Fig. 6, I provide a verticaladjustment as well as that afforded by movement of the slide 105. Inthis arrangement I mount the support 107 'on a pivot 1'20 and securesame in a V-shaped recess 121 in the slide 105. I also provide a pair oftapped recesses diametrically opposed and containing threaded contactmembers 122 and 123 so positioned as to bear upon the support 107 and0scillate it about the pivot and hold the same imposition to which itmay be adjusted, by rotating said contact members 122 and 123, as willbe readily understood.

The means of rotating the model 31 and block 26 in the swinging framehas already been described and in order to feed the cutter carriage 66and contact carriage 100 longitudinally of the work on their respectiveslides, I secure same together by a pair of telescoping bars 125 and 126adapted to be united in adjusted position by passing through a block 127and clamped by a screw 128. Thus they will be fed 'in unison, this beingthe usual construction.

In order to effect the feeding movement of the carriages 66 and 100, Iprovide pulleys 130, on the shaft 50, and 131, on the shaft 133,arranged for variable speeds, said shaft 133 being mounted in the frame1, 1 and carrying at its outer end a pulley 134 to which the belt 135 isled to a pulley 136 on a shaft 137 at the base of the frame.

This shaft 137 has a worm 138 arranged to mesh with the gear 139 on ashaft carrying a gear 146 and through pinions 141 and 142 operating on arack secured underneath the carriage 66 and thus imparting desired feedto the cutter head 25 and model contact ball 30.

An important feature of my present invention, as briefly explained andabove outlned, is the arrangement of the novel ball 30 cooperating withthe novel cutter head 25, permitting the lathe to operate much moreefiiciently than has heretofore been possible and to follow involvedcontours on the model of extremely small radius.

Referring to Fig. 11 is illustrated in diagrammatic form a crosssectional portion of a typical shoe last which is rotated in the latheand around which the model wheel rolls. As above explained, it hasheretofore been found impractical to have a model wheel rolling on anirregular form such as a last 160 of less than seven inches in diameter,such a wheel being shown in dotted lines at 161. Consequently, as thelast 160 and wheel 161 rotate, swinging the frame carrying the block 26to be cut, the cutter, irrespective of its size, position or shape willfollow on the block 26 the movement effected by the wheel 161. In otherwords, the lathe could not cut a sharper angle or a concave contourwhich was on a radius less than that of the model wheel 161. By myimprovement with the ball 30 of extremely small diameter and cooperatingwith the mushroom formed cutter 25, it will be seen on reference to Fig.12 that a last 160 having a curved contour at 162 will be readilyfollowed by the ball 30 and the same contour reproduced in the block 26by my cutter 25.

It is customary at present to make lasts with such small and sharplycurved recesses in the tarsal arch supporting feature.

ably, also, the ball 30 is countersunk to receive 'ball of the last toprovide a corresponding meta tarsal arch supporting projection orstructure in the shoe to be made thereon. He'ret'ofore it has beenimpossible in any last turning lathe to provide either afollower or acutter which would turn out a last including the recess for the meta-Consequently "all such prior devices have had to be made by laboriousand highly skilled hand labor.

Furthermore, it was impossible to accurately position and form suchrecesses by hand gouging. By my present invention, as clearlyillustrated in Figs. 13 and 14, my contact ball 30 and cutter 25 willreadily follow and reproduce as sharply a concave metatarsal recess asis ordinarily desired in a last, as shown at 165 m the last 16 1, Figs.13 and 14. This feature is a distinct improvement in the art of lastturning or in turning any irregular articles with concave contours ofless radius than that of the former seven inch model wheel which rollsin contact with the model to be reproduced. a

A further important feature is-that I provide.

the contact ball 30 and the smallest cutting diameter of the cutter 25on substantially the same radius. Thus the contact ball and the cutterautomatically follow and accurately reproduce curves of an extremelysmall radius, which were heretofore deemed impossible on turningmachines, as well as following and reproducing all other portionsheretofore made on turning lathes of this kind. In fact, I can make thecontact ball and cutter of sufficiently small radius to cut on concavecontours of a fraction of an inch.

Furthermore, the fact that my improved lathe and apparatus, when usedfor turning lasts, is of greatly increased accuracy than heretoforepossible, also eliminates to a large degree the subsequent operation ofshaving the last to remove ridges left by the feeding of the turningcutter. This is a great saving and a most important and novel feature.

My invention is further described and defined in the form of claims asfollows:

1. In a turning lathe of the kind described for reproducing irregularforms, a pattern, a block, means to rotate the pattern and the block inunison, means carrying a rotating cutter adapted to operate on saidblock, means controlling the relative position of the cutter and blockdetermined by the pattern, and a motor carried by the machine to rotatethe cutter, means for feeding both the cutter and the motor past theblock during the cutting action, and means supporting said cutterindependently of the motor.

2. In a turning lathe of the kind described, means to support and rotatea last pattern, means to support and rotate a block on which the last isto be reproduced from said pattern, a cutter adapted to operate on saidblock, and means controlling the relative position of the cutter and theblock determined by said pattern, guideways on which the cutter issupported, a motor to actuate said cutter, separate guideways on whichsaid motor is supported, means to rotate the cutter from the motor, andmeans to feed both motor and cutter in unison from a single source ofpower during the last cutting operation.

HAROLD W. SPRAGUE.

